Method of operating polyphase induction-motors.



LAB/1MB.

METHOD OF OPERATING POLYPHASB INDUCTION MOTORS.

APPLIOATION :ILED JULY 6, 190B.

v Patented Jan 5, 1915.

2 SHEETS-SHEET l.

INVE TOR ATTORNEY WITNESSES:

B. G. LAMME'.

METHOD OF OPERATING POLYPHASE INDUCTION MOTORS.

APPLICATION FILED JULY 6, 1908.

1,123,321, 7 I Patented Jan.5, 1915. I

2 SHEETS-SHEET 2-.

WITNESSES: INVENTORA BY W 6. QM QXQW ATTORNEY UNITED STATES EATENT OFFICE.

BENJAMIN G. LAMME, 0F PITTSBURGH. PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, OF EAST PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

METHOD OF OPERATING POLYPHASE INDUCTION-MOTORS.

To all whom it may concern:

Be it known that I, BENJaMIN G. LAMME, a citizen of the-United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Operating Polyphase Induction-Motors, of which the following is a specification.

My invention relates. to induction motors, and it has for its object; to provide a method of and a means for starting or operating polyphase induction motors-that obviate the necessity for employing auto-transformers in connection therewith.

Figure 1 of the accompanying drawings is a diagrammatic view of a three-phase motor and a controller embodying my invention. Figs. 2, 3, 4 and 5 illustrate, diagrammatically, the arrangements of the motor windings -for' the various positions of the controller of Fig. 1.' Fig. 6 is a diagrammatic view'of'a-two-phase motor and a controller embodying ,the invention, and Figs. 7, 8 and 9 illustrate, dia-grammatically,-the connections of the motor windings for the. various positions of the'controller of Fig. 6.

Tl-ie'm'otor comprises a secondary member 1 of the squirrel-cage or anv other'suit able type, and aprimary winding divided into six section 2, 3, 4, 5, 6 and 7 two for each phase. The sections 3, 4 and 60f the primary winding are permanently connected in star arrangement, the common terminal or neutral point of the winding being connected to three stationary contact fingers 8, 9 and 10 of the controller, and the other terminals of the said sections being connected to the contact terminals 11, 12 and 13, respectivelyg of the controller. The remaining sections 2, 5 and 7 of the primary winding ofthe motor are connected, respectively, between difierent pairs of contact fingers of the controller in such a manner that when thecontroller segments engage the contact fingers along the broken line a, the two sections of each phase of'the windingwill be connected in series relation, as indicated in Fig. 2. This will be readilyunderstood by following the circuit for one phase of the winding from a supply conductor 14 through devices bearing reference characters 15, 16, 17, 7-, 18, 19, 13 and 6, the circuits for the remaining phases being similar.

As the controller is moved to the position- Specification of Letters Patent.

, Application filed July 6, 1908. Serial No. 442,220.

Patented Jan. 5, 1915.

indicated by the broken line b, the sections 6 and 7 of one phase of the winding are changed from series to parallel relation, as shown in Fig. 3, the two parallel circuits being respectively by way of devices bearing reference characters 14, 15, 16, 17, 7, 18, 19 and 8 and by way of devices 14, 15, 16, 13

and 6. As the controller is moved through i the succeeding positions 0 and d of the controller, the sections of the remaining two phases of the primary winding are changed in succession from series to parallel relation, the" circuits being similar to those just described. 1

.VVhen the sections of each phase of the winding are arranged in series relation, as shown in F ig. 2, the torque exerted is approximately 25.% of the normal torque of the motor, or that obtained with the connections shown in Fig. 5, since the arrangement is equivalent to applying one-half of normal voltage of the motor. lVith the winding arranged as shown in Fig. 3, the torque eXerted is from 35 to 40% of that exerted when the sections of the windings are connected as shown in Fig. 5, and with the arrangement shown in Fig. 4, a torque of from 65 to 70% of normal full load torque is obtained. While some unbalancing of the currents in the several phases of the winding occurs when the unsymmetrical arrangements shown in Figs. 3 and at are employed, but little harmful effect upon the torque is caused, as it is known that the torques, with these arrangements, are approximately the same per kilovolt-ampere input to the motor as if balanced conditions existed.

' In certain or manyinstances it may be unnecessary to provide for as many gradations in the starting torque as are arranged for in Fig. 1, and for that reason-one or the other of the connections illustrated in Figs.

a, the two sections of each phase or the primary winding of the motor are connected in series relation, the circuit. for one phase be ing byway of devices bearing reference characters 24, .25, 26, 20, 27,28, 29, 22, 30,!

31 and 32, and the-circuit of the other phase of the-winding being similar thereto. In position b of the controller,sections 20 and". 22"of one phase of the winding are connected inparallel relation as shown in-Fig 8f, the two-parallel circuits being, respectively, b'yiwaypf 'devices bearing reference charactersfl l, 25,26, 20, 27, '31 and. 32, and by w'ayof devices 24,25, 29,22, 30, 31 and '32." In'position 0 ofthecontroller,' the sec tions 21: and 23 of the otherphase of the winding arealso connected in parallel relation, thecircu ts being similar to those just describedforhpositi I r I I claim as my invnfid 1. The method'of starting ,'i olyphasc in duction 'motor having afprimary winding compri'siriga plurality of-sections for each phase of current which consists in Ifirstmaldn'ga'supply-circuit connectionfor each 'phasecf current, with the sections corresponding to a plurality of-phases connected in series relation, andthen successively con nectmg the sections correspon'chngto the res'pective' phases in arallel. relation.

/ phases parallel relation to gradually re- 2, The'method 0 starting a polyphase induction motor having a primary winding comprising "aplurality-of sections correspending to each phase ofgcurrent which consists in -first connecting the sections, cor

responding to each of the phasesinseries relation and then successivelyconnecting the sections corresponding tothe respective duce the resistance to current flow-in the wrndingand to permit-an increase in the v I torque exerted by the motor. v

' The method of operating a polyphase induction motor having a primary win g comprising a plurality-of sections for each phase of current whichj'consists in changing the sections corresponding to a plurality-of primary winding comprising a plurality of consists in-first connecting the sections corv sections. for each phase of current which responding to the several phases in series relation and then successively changing the sections corresponding to a plurality of phases to parallel relation. I v

5. The method of operating a polyphase induction motor having a star-connected primary winding comprising a plurality of sections for each phase of current-which consists in connecting the sections -pertain ing to each phase inseries relation and then sections -in parallel relation. Y s In testimony whereof, I have hereunto subscribed my name this 30th day of June,

r r ,l 1 w Ban e. L AMME;

successively com1ecting the di1i'erent ph.se

a Witnesses: 4 I I EnizABn'rr: Lmnes'ronn, v .BmNEY HINES. 

